RESUMEN
To identify and analyze the virulence of a bacteria strain isolated from the blood of a patient with suspected Streptococcus suis (S.suis) infection in a hospital of Beijing,we inoculated the bacteria strain isolated from the blood of the patient to the Columbia with sheep blood agar plate,after Gram staining and microscopical examination,serum agglutination test,VITEK 2 Compact microbial identification system test and matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) test,S,suis species specific gene 16SrRNA,S.suis species serotype 2 specific virulence gene capsule polysaccharide 2J (cps2J) and virulence gene muramidase-released protein (mrp),hemolysin (sly),extracellular factor protein (ef),glutamate dehydrogenase (gdh) genes,fibronectin-binding protein (fbps),glyceraldehyde-3-phosphate dehydrogenase (gapdh) genes and virulence correlated gene orf2 were further detected by PCR.Results showed that the suspicious bacteria strain of S.suis was identified as S.suis type 2 (S.suis 2) by conventional methods,MALDI-TOF-MS and PCR.PCR results showed that cps2J,sly,ef,gdh,fbps,gapdh and or f2 genes were positive,and mrp gene was negative.In conclusion,the bacteria strain isolated from the patient's blood is sly+/ef+/mrp-virulent S.suis 2.
RESUMEN
To understand the enolase(eno)gene and its product in Streptococcus suis serotype 2(S.suis 2), bioinformatics was adopted to analyze the whole genome sequence of the Chinese strain 05ZYH33 of S.suis 2.A highly homologous eno gene was unveiled by the genome-wide mining.A pair of specific primers was designed for the eno,and the target DNA fragment of 1.3 kb was successfully amplified using the genomic template of 05ZYH33.Subsequently,eno gene was inserted into pMD18-T vector,and then subcloned into prokaryotic expression vector pET32a,generating a recombinant expression plasmid pET32a::eno.The resulting plasmid was confirmed by direct DNA sequencing and transformed into E.coli BL21(DE3) competent cells.Protein expression analysis showed that a 75 kD protein can be observed in 12% SDS-PAGE,indicating that the recombinant 6His-fused ENO protein can be produced in E.coli under the induction of IPTG.Westem-blot experiment demonstrated clearly it shares strong specific antigenicity. Moreover,ELISA result suggested that ENO can occur on the surface of 05ZYH33 strain.Together,our data ENO can function as a novel antigen,and may play pivotal roles in the severe infection of S.suis 2.